TITLE:
Air-Ground Temperature Coupling: Analysis by Means of Thermal Orbits
AUTHORS:
Vladimir Cermak, Louise Bodri
KEYWORDS:
Thermal Orbits, Temperature Monitoring, Air Temperature vs Ground Temperature, Climate Change, Subsurface Temperature
JOURNAL NAME:
Atmospheric and Climate Sciences,
Vol.6 No.1,
January
27,
2016
ABSTRACT: Long-term measurements of air, near-surface (soil)
and ground temperatures that were collected between 1994 and 2013 at the drill
site of the Geothermal Climate Change Observatory (Prague) were analyzed to
understand the relationship between these variables and to reveal the
mechanisms of heat transport at the land-atmosphere boundary layer. The 2D Thermal Orbit (TO) method
was applied to detect regularities that were hidden in noisy and highly
variable temperature time series. The results showed that the temperatures at
shallow depths were affected by surface air temperature (SAT) variations on
seasonal and annual time scales and could be regarded as an accurate proxy for
low frequency temperature variations at the Earth’s surface. Only low-frequency/
high-amplitude surface temperature variations penetrate into the subsurface
because of strong damping and the filtering effect of the ground surface. The
borehole temperatures have good potential to capture temperature variations
(periodicities) over long time scales that cannot be detected in the SAT series
themselves because of the interference of higher frequency noise. The TO
technique is a useful and powerful tool to quickly obtain diagnostics of the
presence of long periodicities in borehole temperature time series.